1. Field of the Invention
The present invention relates to an adjustment mechanism for moving the telescope of a theodolite.
2. Description of Related Art
Prior art theodolites and total stations typically contain a mechanism to provide coarse and fine movement of the telescope and locking mechanism that locks the telescope in position so that the coarse and fine mechanism can be used to move the telescope. Prior art theodolites and total stations therefore have two separate knobs on both the vertical and horizontal mechanisms that move the telescope in a vertical and horizontal direction. The locking mechanism locks a lever on the axis of the telescope and the coarse and fine mechanism operates against the end of this lever to move the telescope, the reverse direction of the lever, against the movement of the coarse and fine mechanism is typically achieved by a leaf or coil spring. The big problem with this type of mechanism is that the operator is continuously having to unlock and re-lock the locking mechanism in order to return the course and fine mechanism to the center of their run as their lateral movement is limited by the spring that acts against them. This is a great inconvenience to the operator as it takes up valuable time and it makes it almost impossible to track a moving target. It would be desirable to provide a theodolite or total station with a continuous coarse and fine adjusting mechanism for each of the vertical and horizontal alignment of the telescope, and that each mechanism should have only one knob that would move the telescope continuously.